Conversion of hydrocarbons



- alhylation reactions the molar ratio of isopr iii Tl.

"Poientedoct. 31,

UNITED s urs s PATENT OFFICE commiss on on mnocnnnons non n." Carmody.ond, Incl, asslxnor to Standard Oil Company, Chicago, 111., aoorporation of Indiana No Application March 28,

Serial No. 326,468

' I 2 Claims. This invention relates to a-process for the procarbonsfrom hydrocarbons of lower, molecular weight and relatesz'noreparticularly to a process for the lntcsaction of paramnic hydrocarbonsfor ductionof high octane number liquid hydro-.

the production of normallyliquid hydrocarbons suitable for aviationgasoline.

It is an object of this invention to provide a process wherein param nichydrocarbons, and particularly is'oparafinic hydrocarbons, are reactedto form isopar ii c hydrocarbons othlgher molecular weight. Anotherobject of this invention is to provide a process wherein isoparafhnlchydrocarbons of low' molecular weight are reacted in the presence of analcohol. It it a further object of invention to provide a.

process for the production of hieh oce numher-gasoline by thecondensation of isopar r hydrocarbons having at least four carbon atomsper molecule in the presence of a promoter such as an alcohol. *l:objects and advantages will become appent as the description oi myprocess proceeds. v

The almlation of hydrocarbons, particularly isobutane and isopentanewith olefins'in the presence of sulfuric acid for the production of highoctane number hydrocarbons on within the gasoline boiling range is wellr in to olefin reacting is always 1:1 or less. This is obvious when itis remembered that onemol oi isoparac hydrocarbon reacts with on moi ofolefinic hydrocarbon to form 'onem'ol or isoparatflnic hydrocarbon ofhigher molecular weight. In the event that the higher lsoparal finichydrocarbon formed is further alkylated under certain circumstances withan additional moi of olefihic hydrocarbon, themolar ratio of originalisoparac hydrocarbonto olefinlc hydrocarhon is reduced to less than 1:1.I have discovered, however, that by carrying out the the absence'of anicon the above example.

. will be noted that the primary products from process under similarconditions in the absence- .oi ole but with-the addition of an alcoholtion can be made to react in suchmanmore than one mol of isoparaflinichydrocarbon reacts per mole! alcohol with the formation of higherboiling-liquid hydrocarbons characterized by high octane number. theprocess the alcohol is simultaneously con-' During- .1. hydrocarbonshaving an isomeric-- verted to a pee hydrocarbon which can j beseparated from'the product or can be left blended therewith if desired,in order to provide a balanced iuel suitable. both in boiling range andoctane number for in aviation engines.

a y particular theory a v t0 the mechanism by which this reectiontakesplace, it is, my sus- As an example 01' my process, 280 parts by weightof isobutane wasi'nixed by violent agitation with 423 parts by weight or98.6% sulfuric acid to form an emulsion at a temperature or about to F.An inert diluent, normal heptane, was added to lower'the vapor pressureof the isobutane. To the emulsion thus' formed was added 101 parts byweight of tertiary amyl alcohol, the addition being made over a period.

of approximately 3*hours. The reaction was carried out over a totalperiodof 6.25 hours.. A

- total of 161 parts by weight'oi product boiling above .pentanes wasproduced. The weight percent yield of product, exclusive oi unreactedfeed stock, was 200% based on the potential olefin in the alcohol whichwas distributed as iollows:

' Fractionation of product:

that added as inert diluent was recovered from the C1 out. The data havebeen corrected for this. A parallel run was made with the same amount oftertiary amyl alcohol and normal 'heptane at'the sameoperatingconditions but in :ii c hydrocarbon. The normal heptane wasrecovered quantitative- 1y. thus indicating that thisdiluent is inert inetely tltiiiata. It

All products were compl the reaction are pentanes and octanes.Ordinarily it would be expected that "alwlation" would take placebetween the isobutane and the tertiary amyl alcohol with the formationof an isononane and the elimination of In'. placeot this it appears fromthe distribution of v the products that the isobutane has reacted withitself with the formation of isooctane and that the tertiary amylalcohol has been convertedtc isopentane, This is further emphasized bythe fact that in this example 3 mols o! isoparamn per mol of alcoholreactednnd that a corresponding amount of isopentane was produced.

Although I do not intend-to be restrictcdto section that underth: setforth hydrogen or a hydrogen radical, or a proton is removed from theisobutane, and used for the hydrogenation of the tertiary, amyl alcoholwith the accompanying production of water therefrom. The dehydrogenatedisobutane either simultaneously or subsequently interacts to form anisooctane.

A similar experiment was carried out employing 319 parts by Weight ofisopentane and 580 parts by weight of 98.6% sulfuric acid. In this caseno inert diluent was used. Over a period of 5.3 hours '75 parts byweight of tertiary butyl alcohol was added at a'temperature of 70 to 80F. and the reaction continued for a total period of 6 hours. Productequivalent to 237 parts by weight, exclusive of unreactedfeed stock, wasobtained giving a weight yield of 423% based on the the potential olefinin the alcohol. In this case 2.7 mols of isopentane per mol of alcoholreacted.

The product consisted of 65 parts by weight of isobutane and 172 partsby weight of hydrocarbons (exclusive of the unreacted isopentane)boiling in the gasoline range. The higher boil- All products werecompletely saturated.

In this case it will be noted that there is a more even distribution ofproducts between the hexanes, octanes, nonanes and decanes which isbelieved tobe due to the tendency of the decanes which would be formedby the interaction of the isopentane to break down under the-conditionsemployed here into Cs and C4 hydrocarbons. The isobutane produced fromthe butanol or from the disproportionation of the decane may then reactto produce Cs.

A run employing secondary butyl alcohol and isopentane was carried outas follows:

424 parts by weight of 98.6% sulfuric acid, 314 parts by weight ofisopentane and 73.5 parts by weight of secondary butyl alcohol werereacted as described above at '70-'78 F. for 6.25 hours to yield 42parts by weight of isobutane and 144 parts by weight of hydrocarbonsboiling in the gasoline range exclusive of unreacted isopentane. Thisrepresents a yield of 334% by weight based on the potential butylene inthe alcohol, and corresponds to 2.2 mols of isoparaffin per mol ofalcohol reacting. The gasoline hydrocarbons had the followingdistribution:

. Vol. Cs 22.7 C7 Ca 0 C9 I 50.0 C1o+ 27.3

ucts such as aviation .safetyfuel, a feed material consisting ofisoparafllnic hydrocarbons having a molecular weight of 86 or highershould be used.

Broadly speaking, my process may be carried out at temperatures limitedonly by freezing temperature of the sulfuric acid as the lower limit,and the oxidation of the hydrocarbons by the sulfuric acid as the upperlimit. A range from about 10 F. to 110 F. is permissible, and,preferably, I may use a temperature of from about 30 to about 80 F.Sulfuric acid having an acidity of from 85% to 101%, preferably about96%, is a suitable catalyst for my process. It is desirable in all casesthat sufficiently violent agitation be used to insure intimate contactbetween there- I'his may be accomactants and the catalyst. plished bystirring mechanisms, by jet injectors,

or by any other suitable mechanical means. |An

inert diluent may be employed to reduce the vapor pressure of thereactants or the reactants may be maintained in the liquid phase bysuperatmospheric pressure. The presence of inert gases,

lsuch as normal parafflns which are ordinarily found mixed withisoparaffins in hydrocarbons from such sources as the crack ng ofpetroleum and in natural gas or casinghead, is not objectionable, altho,since they do not enter into the reaction, they are not desirable. Iprefer to, carry out the reaction using an excess of isoparaflinichydrocarbons above that theoretically necessary to react with thealcohol. There should be present at least two mols or isoparafiln forevery mol of alcohol, and preferably more than two mols of isoparafiinfor every mol of alcohol. a

It has been found that 'isopropyl alcohol is not effective for myprocess, which I have designated dehydroalkylation. When using isopropylalcohol a direct reaction between the alcohol and the. isoparafiin isobtained with the formation, forexample; of isoheptane, when usingisobutane with isopropyl alcohol.

When employing a butyl alcohol in my process one of the primary productsis isobutane which can be utilized in a corresponding dehydroalkylationreaction employing an alcohol of four or more carbon atoms or it may befittingly employed in an alkylation reaction using isopropanol and anisoparaflin as the feed. When using tertiary amyl alcohol in my process,the isopentane formed can be retained in or' suitably blended with thedehydroalkylation product since generally it is desirable to increasethe volatility of the aviation fuel, and isopentane has a sufflcientlyhigh octane number to render its presence valuable in the production ofan aviation gasoconcentration or by fortification with sulfur trioxideor fuming sulfuric acid. The diluted acid can also well be employed in apolymerizationrecess in which oleflnic gases are converted to liandtri-oleflns in the presence dilute suluric acid or if sufllcientlydiluted, the acid can )8 directed to an alcohol-producing unit forabsorption of olefins and the formation of alcohol suitable for use inmy process. Further modification and extrapolations of my process willreadlly occur to one skilled in the art.

My process is notable in that it is' ordinarily considered,thermodynamically, that twoparaflin molecules cannot form a higherparaflin by the elimination of a. molecule of hydrogen. By my process,however, a hydrogen acceptor" is provided, which furnished a meanswhereby the hydrogen apparently can be withdrawn from the reaction,leaving the dehydrogenated parafllns available for reaction. In spite ofthis hypothesis, however, it is indeed surprising that more than one molof isoparaflinlc hydrocarbon reacts per mol of alcohol rather than onemol or less of. the isoparaflln feed stock reacting with each mol ofolefin as in the case of the well-known alkylation processes. I

It should also be pointed out that by my process hydrocarbons ofgasoline-like properties characterized by high octane numbers areproduced with greater yields than the usual commercial synthesis, andwithout the necessity for involved recycling in order to utilize as faras possible the available paraiiinic feed stock.

, I- claim: g

1. In a process of producing a saturated hydrocarbon from isoparaflinicand oleflnic hydrocarbons, the steps of absorbing olefin-containinggases in dilute sulfuric acid, diluting the sulfuric acid further toseparate out the alcohols, con tactingthe resulting alcohols with saidisoparaffinichydrocarbons in the presence of concentrated sulfuric acidat a temperature whereby a higher molecular weight saturated hydrocarbonand water are produced thereby diluting the sul furic acid and supplyingthe diluted sulfuric acid to the first-mentioned absorption step.

2. In a process of producing a saturated hydrocarbon boiling in thegasoline range from isoparaflinic and olefinic hydrocarbons having morthan three and less than six carbon atoms per molecule, the steps ofabsorbing the oleflnic h: drocarbons in dilute sulfuric acid, dilutingthe combined stream of, absorbed oleflns and sulfuric acid to recoverthe coresponding alcohols, contacting the isoparafiinic hydrocarbons andsaid alcohols in the presence of sulfuric acid having 'an acidity ofbetween about 85 and about 101% at a temperature of between about and F.to produce'isoparafllnic hydrocarbons boiling in the gasoline range, asaturated hydrocarbon corresponding to the alcohol and water, recoveringthe resultant diluted sulfuric acid and supplying the diluted acid tothe first mentioned olefin absorption step.

DON a. cARMo'DY.

